The aim of the present study was to construct the 125I-replication-selective oncolytic adenovirus (RSOAds)-human telomerase reverse transcriptase (hTERT)/prostate specific antigen (PSA) nuclide-oncolytic virus marker by labelling the hTERT/PSA double-regulation replicative oncolytic adenovirus with 125I nuclide, and investigate the influence of viral markers under various reaction conditions on labelling efficiency. N-bromosuccinimide (NBS) was used as the oxidizer for 125I labelling, and the best conditions for labelling were identified through the reactions between oncolytic adenovirus at various concentrations and NBS. Dosage of 125I, reaction duration, pH values and reaction volume were respectively evaluated to determine their effects on the labelling efficiency of 125I-RSOAds-hTERT/PSA nuclide-oncolytic adenovirus markers. Purified nuclide-oncolytic adenovirus markers were isolated by gel-filtration chromatography; paper chromatography was performed to assay the radiochemical purity of 125I-RSOAds-hTERT/PSA markers at various time points. Radiochemical purity of 125I-RSOAds-hTERT/PSA was >95%, and could be maintained at 4°C for 7 days. The best reaction conditions were set as follows: 0.5 µl of 125I (~0.2 m Ci, 7.4 MBq); 25 qg of NBS; 100 µl of 8×109 VP/ml 125I-RSOAds-hTERT/PSA virus solution; 30 min of reaction duration; pH 7.5; 120 µl of PBS. Labelling hTERT/PSA double-regulation replicative oncolytic adenovirus with 125I was identified to be available, and the radiochemical purity of acquired virus markers could be maintained under specific conditions.
Keywords: 125I; castrate-resistant prostate cancer; human telomerase reverse transcriptase; prostate specific antigen; replication- selective oncolytic adenovirus.